Commit adf7a0a5 authored by Yury Delendik's avatar Yury Delendik Committed by Derek Schuff
Browse files

[WebAssembly] Use TargetIndex operands in DbgValue to track WebAssembly operands locations 

Extends DWARF expression language to express locals/globals locations. (via
target-index operands atm) (possible variants are: non-virtual registers
or address spaces)

The WebAssemblyExplicitLocals can replace virtual registers to targertindex
operand type at the time when WebAssembly backend introduces
{get,set,tee}_local instead of corresponding virtual registers.

Reviewed By: aprantl, dschuff

Tags: #debug-info, #llvm

Differential Revision: https://reviews.llvm.org/D52634
parent 538b485c

llvm/include/llvm/BinaryFormat/Dwarf.def

+2 −0
Original line number Diff line number Diff line
@@ -648,6 +648,8 @@ HANDLE_DW_OP(0xa9, reinterpret, 5, DWARF) 
// Vendor extensions:

// Extensions for GNU-style thread-local storage.

HANDLE_DW_OP(0xe0, GNU_push_tls_address, 0, GNU)

// Extensions for WebAssembly.

HANDLE_DW_OP(0xed, WASM_location, 0, WASM)

// The GNU entry value extension.

HANDLE_DW_OP(0xf3, GNU_entry_value, 0, GNU)

// Extensions for Fission proposal.

llvm/include/llvm/BinaryFormat/Dwarf.h

+2 −1
Original line number Diff line number Diff line
@@ -63,7 +63,8 @@ enum LLVMConstants : uint32_t { 
  DWARF_VENDOR_GNU = 3,

  DWARF_VENDOR_GOOGLE = 4,

  DWARF_VENDOR_LLVM = 5,

  DWARF_VENDOR_MIPS = 6

  DWARF_VENDOR_MIPS = 6,

  DWARF_VENDOR_WASM = 7

};



/// Constants that define the DWARF format as 32 or 64 bit.

llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp

+4 −0
Original line number Diff line number Diff line
@@ -879,6 +879,10 @@ static bool emitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) { 
    OS << MI->getOperand(0).getImm();

  } else if (MI->getOperand(0).isCImm()) {

    MI->getOperand(0).getCImm()->getValue().print(OS, false /*isSigned*/);

  } else if (MI->getOperand(0).isTargetIndex()) {

    auto Op = MI->getOperand(0);

    OS << "!target-index(" << Op.getIndex() << "," << Op.getOffset() << ")";

    return true;

  } else {

    unsigned Reg;

    if (MI->getOperand(0).isReg()) {

llvm/lib/CodeGen/AsmPrinter/DebugLocEntry.h

+35 −3
Original line number Diff line number Diff line
@@ -20,13 +20,33 @@ 
namespace llvm {

class AsmPrinter;



/// This struct describes target specific location.

struct TargetIndexLocation {

  int Index;

  int Offset;



  TargetIndexLocation() = default;

  TargetIndexLocation(unsigned Idx, int64_t Offset)

      : Index(Idx), Offset(Offset) {}



  bool operator==(const TargetIndexLocation &Other) const {

    return Index == Other.Index && Offset == Other.Offset;

  }

};



/// A single location or constant.

class DbgValueLoc {

  /// Any complex address location expression for this DbgValueLoc.

  const DIExpression *Expression;



  /// Type of entry that this represents.

  enum EntryType { E_Location, E_Integer, E_ConstantFP, E_ConstantInt };

  enum EntryType {

    E_Location,

    E_Integer,

    E_ConstantFP,

    E_ConstantInt,

    E_TargetIndexLocation

  };

  enum EntryType EntryKind;



  /// Either a constant,
@@ -36,8 +56,12 @@ class DbgValueLoc { 
    const ConstantInt *CIP;

  } Constant;



  union {

    /// Or a location in the machine frame.

    MachineLocation Loc;

    /// Or a location from target specific location.

    TargetIndexLocation TIL;

  };



public:

  DbgValueLoc(const DIExpression *Expr, int64_t i)
@@ -56,8 +80,13 @@ public: 
      : Expression(Expr), EntryKind(E_Location), Loc(Loc) {

    assert(cast<DIExpression>(Expr)->isValid());

  }

  DbgValueLoc(const DIExpression *Expr, TargetIndexLocation Loc)

      : Expression(Expr), EntryKind(E_TargetIndexLocation), TIL(Loc) {}



  bool isLocation() const { return EntryKind == E_Location; }

  bool isTargetIndexLocation() const {

    return EntryKind == E_TargetIndexLocation;

  }

  bool isInt() const { return EntryKind == E_Integer; }

  bool isConstantFP() const { return EntryKind == E_ConstantFP; }

  bool isConstantInt() const { return EntryKind == E_ConstantInt; }
@@ -65,6 +94,7 @@ public: 
  const ConstantFP *getConstantFP() const { return Constant.CFP; }

  const ConstantInt *getConstantInt() const { return Constant.CIP; }

  MachineLocation getLoc() const { return Loc; }

  TargetIndexLocation getTargetIndexLocation() const { return TIL; }

  bool isFragment() const { return getExpression()->isFragment(); }

  bool isEntryVal() const { return getExpression()->isEntryValue(); }

  const DIExpression *getExpression() const { return Expression; }
@@ -162,6 +192,8 @@ inline bool operator==(const DbgValueLoc &A, 
  switch (A.EntryKind) {

  case DbgValueLoc::E_Location:

    return A.Loc == B.Loc;

  case DbgValueLoc::E_TargetIndexLocation:

    return A.TIL == B.TIL;

  case DbgValueLoc::E_Integer:

    return A.Constant.Int == B.Constant.Int;

  case DbgValueLoc::E_ConstantFP:

llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp

+10 −0
Original line number Diff line number Diff line
@@ -241,6 +241,11 @@ static DbgValueLoc getDebugLocValue(const MachineInstr *MI) { 
    MachineLocation MLoc(RegOp.getReg(), Op1.isImm());

    return DbgValueLoc(Expr, MLoc);

  }

  if (MI->getOperand(0).isTargetIndex()) {

    auto Op = MI->getOperand(0);

    return DbgValueLoc(Expr,

                       TargetIndexLocation(Op.getIndex(), Op.getOffset()));

  }

  if (MI->getOperand(0).isImm())

    return DbgValueLoc(Expr, MI->getOperand(0).getImm());

  if (MI->getOperand(0).isFPImm())
@@ -2241,6 +2246,11 @@ void DwarfDebug::emitDebugLocValue(const AsmPrinter &AP, const DIBasicType *BT, 
    if (!DwarfExpr.addMachineRegExpression(TRI, Cursor, Location.getReg()))

      return;

    return DwarfExpr.addExpression(std::move(Cursor));

  } else if (Value.isTargetIndexLocation()) {

    TargetIndexLocation Loc = Value.getTargetIndexLocation();

    // TODO TargetIndexLocation is a target-independent. Currently only the WebAssembly-specific

    // encoding is supported.

    DwarfExpr.addWasmLocation(Loc.Index, Loc.Offset);

  } else if (Value.isConstantFP()) {

    APInt RawBytes = Value.getConstantFP()->getValueAPF().bitcastToAPInt();

    DwarfExpr.addUnsignedConstant(RawBytes);